In a conventional Long Term Evolution (LTE) communications system, a data transmission path between user equipments (UE) needs to pass through an access network entity (for example, a base station (eNodeB)), a core network entity (for example, a serving gateway (SGW) or a packet data network gateway (PDN Gateway)), and the like. Even if data needs to be transmitted between two UEs that are close to each other, data transmitted also needs to pass through the foregoing network entities. Therefore, a large network transmission bandwidth is required, and data transmission efficiency is low. In view of this, a proximity service is proposed.
The proximity service means that two UEs that are close to each other can perform mutual discovery and perform direct communication. The proximity service has high data transmission efficiency, and therefore has many functions. For example, by using a proximity service discovery function, a user can discover a corresponding service provided by a nearby restaurant, cinema, bar, or the like.
In specific implementation of the proximity service discovery function, a party that performs active monitoring is referred to as a monitoring UE, and correspondingly, a party that is discovered or monitored is referred to as a discovered UE or a monitored UE or an announcing UE. In the proximity service, a UE may be a monitoring UE, or may be an announcing UE. A processing procedure of the proximity service discovery function is as follows:
Firstly, the monitoring UE sends an acquisition request for obtaining a discovery filter to a network side, and receives a response message returned by the network side, thereby obtaining the discovery filter.
Secondly, the announcing UE broadcasts a proximity service application code (ProSe application code).
Thirdly, based on the obtained discovery filter, the monitoring UE monitors the ProSe application code broadcast by the announcing UE, and therefore can obtain the ProSe application code broadcast by the announcing UE.
Then, when the monitoring UE obtains the ProSe application code broadcast by the announcing UE, the monitoring UE sends, to the network side, a match report message that is used to obtain a service application identity corresponding to the obtained ProSe application code and related information.
Finally, when the network side receives the match report message, the network side sends, to the monitoring UE, the service application identity corresponding to the ProSe application code, and service data.
During implementation of the proximity service discovery function, some service data completely keeps unchanged, but some service data is updated continuously. For the continuously updated service data, after the monitoring UE obtains, according to the obtained ProSe application code broadcast by the announcing UE, the service data provided by the announcing UE, the monitoring UE cannot learn, according to the foregoing data processing procedure, the updated service data provided by the announcing UE.